source: Children’s Hospital of Philadelphia

Sickle cell disease is the name of a group of inherited blood disorders that is characterized by chronic anemia, periodic episodes of pain and other complications.

The disease affects the red blood cells. Sickle cell disease results when red blood cells make mostly hemoglobin S instead of the normal hemoglobin A. Normal red blood cells are smooth, round and soft; their shape and softness enable them to move easily through the blood vessels to carry oxygen to all parts of the body.

In sickle cell disease, the abnormal hemoglobin S causes the red blood cells to become hard, pointed and sticky and shaped like crescents or sickles. When these hard and pointed red cells go through the small blood vessels, they often get stuck and block the vessels. They also stick to and damage the lining of larger blood vessels. The damaged vessels become scarred, narrowed and sometimes completely closed.